The present invention relates to bakers"" dough processing equipment. More specifically, the invention relates to an improved rounder bar for converting pieces of dough divided from streams of dough into rounded spherical pieces or dough balls as the pieces of dough are conveyed along a surface conveyor of a dough processing path.
In a typical commercial bread making process, baker""s dough, which is primarily made of flour and water, is blended in a large mixer. A particularly high water content usually is desirable in the dough composition formed in the mixer because a high water content tends to make a softer baked product. Gluten, which is a component of flour, absorbs and retains the water which is added to the mixer so that a dough of a sticky paste-like consistency is made. After mixing, the sticky dough is then transferred to a stuffing pump which forms the dough into a stream or moving bar that passes through a conduit to dough processing equipment. The processing equipment can include, among others, a dough distribution manifold which distributes the stream of dough into multiple streams of dough, a dough divider which divides the dough streams into pieces of dough of equal volume and deposits the dough pieces onto a continuous moving conveyor belt of a surface conveyor for further processing along a processing path.
Due to compressing, shearing and cutting action inherent in the dough dividing process, divided dough pieces tend to lose a portion of their gas which forms in the dough and which allows the dough to rise. Accordingly, each dough piece must be allowed to regain some of the gas lost during the dividing process. Therefore, a dough piece typically is rounded immediately after being divided in order to acquire a desired spherical shape and in order to develop an outer skin on the dough piece which will retain freshly produced gas. The outer skin also provides the benefit of reducing the stickiness of the dough piece, thereby providing a dough piece which is better suited for processing by dough processing equipment.
Typically, divided dough pieces are delivered by gravity to the upper surface of an endless belt-type conveyor which is provided with a plurality of stationary rounder bar assemblies which are positioned parallel to each other and extending along the length of the belt and which are angularly offset from the direction of travel of the belt. Rounder bar assemblies of this type are disclosed in U.S. Pat. Nos. 4,008,025, 4,306,850, 5,264,232, 5,270,070, 5,356,652, and 5,714,178. Each of the rounder bar assemblies has a concave shaping surface extending angularly along the direction of travel of the belt and facing the on-coming dough pieces. Each of the concave shaping surfaces form elongated pockets or tunnels with the belt for contacting and shaping the surfaces of the dough pieces as the dough pieces are moved along the rounder bar by the conveyor belt. During the rounding of dough pieces, it is desirable to maintain each rounder bar in light continuous contact along its full length with the belt. If contact between the round bar and the belt is excessive, friction can create undesirable heat and can be destructive to the belt. If, however, there are gaps between a rounder bar and the belt, a dough piece can be subject to a nibbling action resulting in some of the dough leaking between the rounder bar and the belt and the spherical dough pieces becoming unequal in size.
Additionally, it is desirable to have the belt of the conveyor kept as flat as possible during the processing of dough pieces so that a rounder bar can more easily conform to the shape of the belt. In order to form the upper surface of the conveyor belt as flat as possible, some prior art conveyors incorporate flat belt support sheets or beds formed of substantially rigid sheet metal which are mounted below the belt and in support relationship with the belt so that the lower surface of the belt contacts and slides on the upper surface of the bed. However, belts can incorporate a seam where the ends of the belt are joined together, thereby creating a hump or raised segment in the belt. Therefore, most rounder bar assemblies are likely to have difficulty in forming a continuous seal against the moving surface of the conveyor belts.
When a dough piece is dropped on the surface of a conveyor and contacts the concave shaping surface of a rounder bar, the resistance applied by the rounder bar to the dough piece causes the dough piece to decelerate from the speed of the belt and to rotate on both the surface of the rounder bar and on the surface of the conveyor. This behavior is caused by the frictional engagement of the outer surface of the dough piece with the shaping surface of the rounder bar and causes the dough piece to take on an approximately round shape, flattened only where it contacts the belt, as the dough piece is forced to rotate about various axes while passing down the length of the rounder bar. However, since the dough piece is no longer traveling at belt speed, the dough piece is rolled and reoriented along the belt as the dough piece engages the rounder bar, usually allowing the dough piece to roll over any portion of the belt that has a hump or a trough. However, due to the inability of the prior art rounder bar assemblies to fully conform to humps or troughs in the surface of the conveyor belt, dough from a dough piece can leak between the lower edge of the stationary rounder bar and the facing surface of the moving conveyor belt as the dough piece is reoriented along the belt.
As shown in U.S. Pat. No. 4,306,850, some rounder bar assemblies incorporate a flexible foot member which is telescopically disposed within a slot formed along the bottom edge of the rounder bar so that the foot extends downwardly from the rounder bar for contacting the conveyor belt. A biasing means in the form of a strip of silicon sponge rubber is disposed within the slot behind the foot and urges the foot into contact with the conveyor belt. Additionally, a series of adjustable fasteners, such as screws, are connected to the foot and slide through the rounder bar at intervals along the length of the rounder bar for providing adjustment of the downward force of the foot against the conveyor belt. So configured, the foot can be positioned with a suitable amount of pressure applied against the belt while the silicon sponge rubber allows the foot to retract within the slot of the rounder bar in response to a raised segment of the conveyor belt passing along the length of the foot.
Although these rounder bar assemblies have increased the efficiency of dough processing, the prior art floating foot still allows an undesirable amount of dough to leak between the rounder bar assemblies and the moving belt. This is due to an inability of the floating foot to conform to troughs in the conveyor belt which typically reside on opposite sides or adjacent a raised segment of the belt. As a raised segment and its associated troughs pass beneath the foot of a rounder bar, the raised segment contacts the foot and causes the foot to exert an increased upward force against the sponge rubber located thereabove, thereby urging that portion of the foot to retract within the rounder bar slot and allowing that portion of the foot to conform to the upper portion of the raised segment of the belt. However, the troughs located adjacent the raised segment typically are concavically shaped segments of the belt surface which the foot bridges or spans without fully conforming thereto. Simply stated, the sponge rubber biased foot tends to adequately bias a raised portion of the foot downwardly against a raised portion of the belt surface but does not apply adequate downward force to an adjacent portion of the raised foot to urge the foot into the adjacent recess or trough of the belt surface.
In an attempt to correct this problem, it has been standard practice to lower the rounder bar assemblies against the conveyor belt, thereby compressing the sponge rubber, until a sufficient downward force was developed between the foot and belt so that the foot would conform to the shape of a passing trough. However, this practice can result in more downward force being exerted upon the belt when a raised segment passes beneath the foot and also can require a significant amount of adjustment in order to maintain the position of the foot relative to the belt so that the foot can conform to a trough while preventing the foot from fully compressing or xe2x80x9cbottoming outxe2x80x9d the sponge rubber in response to a raised segment of the belt. If, however, the sponge rubber were to fully compress, damage to the rounder bar and/or the conveyor can result.
Therefore, an object of the present invention is to provide an improved rounder bar which is adapted to conform along its full length with the upper surface of a conveyor belt.
Another object of the present invention is to provide an improved rounder bar which is capable of conforming to both raised portions and troughs which can form in the upper surface of a conveyor belt as they pass beneath the foot of the rounder bar.
Other objects, features and advantages of the present invention will become apparent upon reading the following specification, when taken in conjunction with the accompanying drawings.
Briefly stated, the present invention comprises an improved rounder bar having a body with a floating flexible foot which bears against and conforms to the shape of the upper surface of a moving conveyor belt. In a preferred embodiment, the body of the rounder bar incorporates an elongated downwardly facing cavity or slot extending along the length of the rounder bar. The foot, formed of flexible material, is configured for being telescopically received in the slot of the rounder bar body with the upper portion of the foot being vertically movably retained within the slot of the rounder bar body so that the foot can move between a low, extended position, with the lower portion of the foot in contact with a low spot on the upper surface of the conveyor belt, and a high, compressed position, with the foot retracting upwardly into the slot when the foot contacts a high spot on the conveyor belt.
The upper portion of the slot, above the foot, is filled with a visco-elastic material which, like a hydraulic material, possesses the physical characteristic of direct compression forces applied to it inwardly through its mass so that there is an equal movement of some other portion of the mass in response to the compression applied to the material. Particular care is given to encase the visco-elastic material within the slot about all surfaces of the material, including adjacent the upper surface of the flexible foot in a fixed volume and to minimize the volume of any air that might be trapped between the material and the facing surfaces of the slot and the upper surface of the flexible foot. This encasement of the visco-elastic material avoids the material from expanding in any direction except to push against and displace the floating flexible foot. So configured, when a segment of the flexible foot is urged against a raised segment of the belt passing therebelow and the raised segment of the belt raises a segment of the floating foot in the slot of the rounder bar against the visco-elastic material, the remaining visco-elastic material exerts a substantially uniform, corresponding downward force against other segments of the floating foot which, in turn, displaces the other segments of the floating foot downwardly a corresponding amount into engagement with the low spots under the floating foot on the surface of the conveyor. Thus, the visco-elastic material imparts a corresponding downward displacement of the flexible foot which is proportional to the upward displacement, thereby causing the other segments of the floating flexible foot to conform to troughs or recesses formed in the conveyor belt under the foot. This is accomplished without the necessity of increasing downward pressure across the entire length of the rounder bar, such as by lowering the entire bar toward the belt, as is well known in the prior art.